Archive for the ‘high tenacity nylon’ Category

Attending the IDEX 2017 UAE military trade show and conference? If so please make time to visit us in Hall 7 and booth A02. Until then the latest press release is available at the IDEX website http://www.idexuae.ae/exhibitors/invista?azletter=I the highlighting INVISTA and the CORDURA® brand.

“For fifty years the CORDURA® brand has been innovating durable and reliable fabrics for military gear using nylon 6,6 fiber technologies. Technologically advanced and extremely durable, CORDURA® fabrics stand up to the rigorous physical demands of the military life as well as provide protection from the elements. CORDURA® fabrics cover nearly everything in a soldier’s arsenal where enhanced durability is required. The fabrics are designed to deliver tensile strength, tear strength and abrasion resistance in footwear, apparel and packs to maximize servicemen’s survivability, mobility, combat effectiveness and field quality of life.”

Photo Credit by Jonathan Long

The CORDURA® brand portfolio features hardwearing and versatile fabric technologies designed to be the soldier’s first line of defense in ballistic vests, boots, parachute containers, recon packs, hydration systems, knee pads and more.

ABU DHABI — IDEX Conference 2017, part of the International Defense Exhibition & Conference (IDEX 2017) and Naval Defense Exhibition (NAVDEX 2017), draws participation of leading security and defense decision makers as well as military program managers from across the world.

Themed Disrupting Innovation in Defense and Security , the conference will be held ahead of IDEX and NAVDEX 2017 at the headquarters of the National Archives in Abu Dhabi on Feb. 18. The http://saudigazette.com.sa/ reports that this conference will include three keynote sessions:

Disruptive Emerging Technology and Innovation: A New Military Paradigm,

Fabric fibers that wear out fast, make garments that fail faster. Working within the Protective Products and Equipment (PPE) industry, we are inundated with data, test procedures (whether ISO or ASTM or AATCC), and if honest, scratch our heads to understand how data and test procedures can be used to predict future performance. To add complexity, in many cases the ISO and ATSM test methods do not directly correlate because the test apparatus are different.

We all know humans are good at measuring things and textile engineers are no exception and excel in this area! If we can develop a scientific test to measure how one type of fiber or fabric performs to another; we are happy. For instance, we are pretty good at measuring several independent elements of textile performance one being fiber tensile strength. We then can compare the results from one fiber to another and claim victorious insight. However in looking at staple fibers which are blended for better performance

Photo Jonathan Long

like those found in military uniforms, there are a couple of things that impact strength. Once we compound fibers with other natural or synthetic fibers during the spinning process strength changes. One fiber’s performance shouldn’t be the final determination of how that yarn will perform or how that fabric once woven will perform. However, tensile strength is important (photo NYLON Fiber)

To measure tensile strength, common test methods used in the Technical Military Fabrics worlds you find are ASTM D5034-09(2013) Standard Test Method for Breaking Strength and Elongation of Textile Fabrics (Grab) or Test Method D3822 Standard Test Method for Tensile Properties of Single Textile Fibers. While these tests are great for comparing fibers and fabrics I am not sure they really tell the whole performance story. We rely on tests to predict which fabric will perform better in a military environment where fabric failure from rips and tears in high abrasion areas such as the knees, elbows, and seat are common. Tensile strength alone may not answer that question but is the most common place to start.

What we do know about tensile strength (or think w do) is that its related to “abrasion resistance” (stated as the number of cycles on a machine, using a technique to produce abrasion) and “durability” (here defined as the ability to withstand deterioration or wearing out a garment fabric in use which includes the effects of abrasion) (1). Higher tensile strength is often thought to indicate better abrasion and durability performance.

In addition to tensile strength we want to measure abrasion and there are three dominant tests.

Martindale Abrasion (ASTM D4966) This test method covers the determination of the abrasion resistance of textile fabrics abraded against crossbred, worsted wool fabric. Fabric samples to be mounted flat and rubbed in an enlarging elliptical T shape using a piece of worsted wool cloth as the abrading material. The end is reached when two yarn breaks occur or when there is an appreciable change in shade or appearance.

Tabor Abrasion (ASTM D4060) This test method covers the determination of the abrasion resistance of organic coatings to abrasion produced by the Tabor Abrader on coatings applied to a plane, rigid surface, such as a metal panel.

Wyzenbeek (ASTM D4157) This test method covers the determination of the abrasion resistance of woven textile fabrics using oscillatory cylinder tester. The Wyzenbeek testing process requires samples of the test fabric to be pulled taut in a frame and held stationary. Individual test specimens cut from the warp and weft directions are then rubbed back and forth using an ACT approved #10 cotton duck fabric as the abradant. The end is reached when two yarn breaks occur or when appreciable wear is reached.

Note to product developers and evaluation teams – both test methods are limited to measuring flat abrasion resistance of a textile. Soldiers are fully three dimensional so these tests don’t consider edge abrasion or other types of surface wear that may occur in soldier uniform applications.

Fibers have different tensile strength but they also have different elongation characteristics. When considering fiber properties, fiber tenacity should not be viewed in isolation. Fiber elongation is at least as important – why? If a fiber cant stretch and recover somewhat, that fiber will break sooner than one that has elongation. Elongation is specified as a percentage of the starting length. The elastic elongation is important since textile products without elasticity would hardly be useable. They must be able to deform and return to shape (2).

Photo INTECH

My thoughts about selecting the optimal fabrics and fiber for military technical fabrics are that we should focus more on the mechanisms of failure. How does a fabric fail? I think we can rightly see that a fiber’s tensile strength is critical but so is a fabrics resistance to abrasion – maybe these two measurements can tell us which fabrics are likely to be the most “durable.”

How does failure actually happen? Its related to how a yarn and fabric’s structure is

Photo Abdullah 2006

modified in use. Lets face it – a fabric that is never used will last a long, long time so its something in use that wears a fabric out. In terms of wear mechanism in textiles, abrasion first modifies the fabric surface and then affects the internal structure of the fabric, damaging it (Manich et.al, 2001; Kaloğlu et al., 2003). Good abrasion resistance depends more on a high energy of rupture than on high tenacity at break. Abrasion is not influenced so much by the energy absorbed in the first deforming process (total energy of rupture), as by the activity absorbed during repeated deformation. This activity is manifested in the “elastic energy” or the “recoverable portion” of the total energy. Thus, to prevent abrasion damage, the material must be capable of absorbing energy and releasing that energy upon the removal of load (3).

The mechanical properties and dimensions of the fibers are important for abrasion. Fiber type, fiber fineness and fiber length are the main parameters that affect abrasion. Fibers with high elongation, elastic recovery and work of rupture have a good ability to withstand repeated distortion; so a good degree of abrasion resistance is achieved. Nylon is generally considered to have the best abrasion resistance, followed by polyester, polypropylene (Hu, 2008) (4).

Photo Jonathan Long

Something to think about is what is the optimal mix between fiber tensile strength and elongation and understanding how that mix performs during abrasion testing. If we find that higher tensile strength and greater elongation results in a more abrasion resistant fabric then we can add another test method to our toolbox to provide insight in failure prediction. Fabrics with lower yarn tensile strength and lower fiber elongation should result in poorer abrasion testing and in turn wear out faster in wear and use. Lets test it and see! (Photo natural cotton, key nylon intermediates, hexamethylene diamine (HMD) and adipic acid, Nylon Cotton Yarn and fabric)

Designers often ask “where can I find Cordura fabric in smaller minimum orders?”

Cordura Photo Credit by Le Souk

Part of the integrated fiber group Invista, Cordua has been providing value to customers for more the forty five years. Cordura fabrics has been traditionally known for military and workwear markets because of durability and versatility.

Today, these high tenacity fiber technologies are being featured by active and sports apparel designers. From the classic air-jet textured nylons to ultra-lightweight high tenacity nylon and polyester fabrics, the latest collection from Cordura is available on Le Souk and more information is available at http://www.lesouk.co/about-us